Ive been using these for many years. Good price and no issues with rounding hexes or broken tips. I use a Bosch 12 volt driver with a torque setting and a 1/4 hex drive with these tips. I can't say enough good things about them. Especially the price.

One of the guys at the local track has an off brand gyro screwdriver. It works OK, best thing about it IMO is that it is so weak it won't strip the plastic out by over tightening the screws. He has to go back and hand tighten the screws the last little bit. I've borrowed it and it was a time saver, would not have gotten my truck back together for the next heat race with out it, much faster than using a manual screwdriver.

Thanks for info squid, the good part about the Dewalt is it has a clutch adjuster like an cordless drill so you can dial in your desired tork, the next thing is you can just run in the screw or whatever to almost fully in , then stop the gun then just use it as you would use a regular screwdriver. When not activated its locked up like a regular screwdriver. Also the dewalt has lots of tork too so it must be use with care. The battery life is great too, I got the one with 2 battery (DEWALT DCF680N2) . Regular price $99 in stores .

I use a Ryobi Tek4 screwdriver. Its a 1/4" quick connect and it has an adjustable torque setting.
Dynamite makes a set of metric driver that are 3 inches long and 1/4" drive. They are hardened and work great.